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1.
Proc Biol Sci ; 290(2005): 20231108, 2023 08 30.
Artigo em Inglês | MEDLINE | ID: mdl-37583325

RESUMO

Ecological interactions influence evolutionary dynamics by selecting upon fitness variation within species. Antagonistic interactions often promote genetic and species diversity, despite the inherently suppressive effect they can have on the species experiencing them. A central aim of evolutionary ecology is to understand how diversity is maintained in systems experiencing antagonism. In this review, we address how certain single-celled and dimorphic fungi have evolved allelopathic killer phenotypes that engage in antagonistic interactions. We discuss the evolutionary pathways to the production of lethal toxins, the functions of killer phenotypes and the consequences of competition for toxin producers, their competitors and toxin-encoding endosymbionts. Killer phenotypes are powerful models because many appear to have evolved independently, enabling across-phylogeny comparisons of the origins, functions and consequences of allelopathic antagonism. Killer phenotypes can eliminate host competitors and influence evolutionary dynamics, yet the evolutionary ecology of killer phenotypes remains largely unknown. We discuss what is known and what remains to be ascertained about killer phenotype ecology and evolution, while bringing their model system properties to the reader's attention.


Assuntos
Fungos , Modelos Biológicos , Filogenia , Fenótipo , Ecologia , Evolução Biológica
2.
Ecol Evol ; 12(1): e8558, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35127053

RESUMO

Upon starvation diploid cells of the facultative sexual yeast Saccharomyces cerevisiae undergo sporulation, forming four metabolically quiescent and robust haploid spores encased in a degradable ascus. All endosymbionts, whether they provide net benefits or costs, utilize host resources; in yeast, this should induce an earlier onset of sporulation. Here, we tested whether the presence of endosymbiotic dsRNA viruses (M satellite and L-A helper) correspond with higher sporulation rate of their host, S. cerevisiae. We find that S. cerevisiae hosting both the M and L-A viruses (so-called "killer yeasts") have significantly higher sporulation efficiency than those without. We also found that the removal of the M virus did not reduce sporulation frequency, possibly because the L-A virus still utilizes host resources with and without the M virus. Our findings indicate that either virulent resource use by endosymbionts induces sporulation, or that viruses are spread more frequently to sporulating strains. Further exploration is required to distinguish cause from effect.

3.
Lancet ; 375(9716): 735-42, 2010 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-20167359

RESUMO

BACKGROUND: Trials of statin therapy have had conflicting findings on the risk of development of diabetes mellitus in patients given statins. We aimed to establish by a meta-analysis of published and unpublished data whether any relation exists between statin use and development of diabetes. METHODS: We searched Medline, Embase, and the Cochrane Central Register of Controlled Trials from 1994 to 2009, for randomised controlled endpoint trials of statins. We included only trials with more than 1000 patients, with identical follow-up in both groups and duration of more than 1 year. We excluded trials of patients with organ transplants or who needed haemodialysis. We used the I(2) statistic to measure heterogeneity between trials and calculated risk estimates for incident diabetes with random-effect meta-analysis. FINDINGS: We identified 13 statin trials with 91 140 participants, of whom 4278 (2226 assigned statins and 2052 assigned control treatment) developed diabetes during a mean of 4 years. Statin therapy was associated with a 9% increased risk for incident diabetes (odds ratio [OR] 1.09; 95% CI 1.02-1.17), with little heterogeneity (I(2)=11%) between trials. Meta-regression showed that risk of development of diabetes with statins was highest in trials with older participants, but neither baseline body-mass index nor change in LDL-cholesterol concentrations accounted for residual variation in risk. Treatment of 255 (95% CI 150-852) patients with statins for 4 years resulted in one extra case of diabetes. INTERPRETATION: Statin therapy is associated with a slightly increased risk of development of diabetes, but the risk is low both in absolute terms and when compared with the reduction in coronary events. Clinical practice in patients with moderate or high cardiovascular risk or existing cardiovascular disease should not change. FUNDING: None.


Assuntos
Anticolesterolemiantes/efeitos adversos , Doenças Cardiovasculares/tratamento farmacológico , Diabetes Mellitus Tipo 2/induzido quimicamente , Inibidores de Hidroximetilglutaril-CoA Redutases/efeitos adversos , Distribuição por Idade , Fatores Etários , Idoso , Diabetes Mellitus Tipo 2/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Ensaios Clínicos Controlados Aleatórios como Assunto , Fatores de Risco , Resultado do Tratamento
4.
J Pharm Sci ; 97(5): 1821-30, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-17828732

RESUMO

Intestinal membrane permeability is an important factor affecting the bioavailability of drugs. As a strategy to improve membrane permeability, membrane transporters are useful targets since essential nutrients are absorbed efficiently via specific transporters. For example, there are reports that intestinal hexose transporters could be used as a tool to improve permeability; however, there has been no direct evidence that the transporter protein, sodium/glucose cotransporter 1 (SGLT1), is involved in the transport of hexose analogs. Accordingly, we examined directly whether the intestinal membrane permeability of hexose analogs can be improved by utilizing SGLT1. Three hexose-quinoline derivatives were synthesized and their interactions with SGLT1 were evaluated. Among the three derivatives, the glucose-quinoline molecule exhibited an inhibitory effect on D-glucose uptake by both rat intestinal brush-border membrane vesicles (BBMVs) and Xenopus oocytes expressing SGLT1. In addition, significant uptake of the glucose-quinoline derivative by Xenopus oocytes expressing SGLT1 was observed by both an electrophysiological assay and direct measurement of the uptake of the compound, while the galactose-quinoline derivative did not show significant uptake via SGLT1. Thus, it was directly demonstrated that SGLT1 could be used as a tool for the improvement of intestinal membrane permeability of drugs by modification to the glucose analogs.


Assuntos
Hexoses/metabolismo , Absorção Intestinal , Quinolinas/metabolismo , Transportador 1 de Glucose-Sódio/fisiologia , Animais , Transporte Biológico , Glucose/metabolismo , Humanos , Masculino , Permeabilidade , Ratos , Ratos Wistar , Xenopus
5.
J Pharm Sci ; 96(10): 2582-606, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17549724

RESUMO

Fatty acids, particularly the omega-3 and omega-6 essential fatty acids (EFAs), are considered critical nutritional sources for the developing fetus. The placenta governs the fetal supply of fatty acids via two processes: transport and metabolism. Placental fatty acid metabolism can play a critical role in guiding pregnancy and fetal outcome. EFAs can be metabolized to important cell signaling molecules in placenta by several major isoform families including: the Cytochrome P450 subfamily 4A (CYP4A); Cyclooxygenases (COXs); and Lipoxygenases (LOXs). Peroxisome proliferator-activated nuclear receptors (PPARs) have been demonstrated to regulate a number of placental fatty acid/lipid homeostasis-related proteins (e.g., metabolizing enzymes and transporters). The present review summarizes research on the molecular and functional relevance of fatty acid metabolizing enzymes and the role of PPARs in regulating their expression in the mammalian placenta. Elucidating the pathways of placental fatty acid metabolism and the regulatory processes governing these pathways is critical for advancing our understanding of the role of placenta in supplying EFAs to the developing fetus and the potential implications on pregnancy and fetal outcome. A more complete understanding of placental fatty acid disposition may also provide a basis for nutritional/pharmacological interventions to ameliorate the risk of adverse pregnancy and/or fetal outcomes.


Assuntos
Ácidos Graxos Insaturados/metabolismo , Feto/metabolismo , Receptores Ativados por Proliferador de Peroxissomo/metabolismo , Placenta/metabolismo , Resultado da Gravidez , Animais , Citocromo P-450 CYP4A/metabolismo , Proteínas de Transporte de Ácido Graxo/metabolismo , Feminino , Desenvolvimento Fetal , Humanos , Hipertensão Induzida pela Gravidez/metabolismo , Lipoxigenase/metabolismo , Oxirredução , Placenta/enzimologia , Gravidez , Nascimento Prematuro/metabolismo , Prostaglandina-Endoperóxido Sintases/metabolismo
6.
Am J Manag Care ; 23(9 Suppl): S149-S155, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28978220

RESUMO

In patients with hypercholesterolemia who have atherosclerotic cardiovascular disease and/or familial hypercholesterolemia, a new class of drugs may be helpful in reducing serum levels of low-density lipoprotein cholesterol (LDL-C) beyond maximally tolerated statin therapy. Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors lower LDL-C through a different mechanism of action than standard cholesterol-lowering therapies. Currently approved PCSK9 inhibitors are the monoclonal antibodies alirocumab and evolocumab. Although the drugs produce substantial reductions in LDL-C, cost issues and efficacy in preventing cardiovascular events should be evaluated when considering the adoption of PCSK9 inhibitors in the managed care setting.


Assuntos
Anticorpos Monoclonais/uso terapêutico , Anticolesterolemiantes/uso terapêutico , Controle de Custos/métodos , Hipercolesterolemia/tratamento farmacológico , Programas de Assistência Gerenciada/economia , Inibidores de PCSK9 , Anticorpos Monoclonais/efeitos adversos , Anticorpos Monoclonais Humanizados , Anticolesterolemiantes/efeitos adversos , Anticolesterolemiantes/economia , Controle de Custos/economia , Humanos , Hipercolesterolemia/economia
7.
Artigo em Inglês | MEDLINE | ID: mdl-16766235

RESUMO

A simple, sensitive and specific LC-MS/MS method for the simultaneous determination of sulforaphane (SFN) and its major metabolites, the glutathione (SFN-GSH) and N-acetyl cysteine conjugates (SFN-NAC) from biological matrices was developed and validated. The assay procedure involved solid-phase extratcion of all three analytes from rat intestinal perfusate using C2 extraction cartridges, whereas from rat plasma, metabolites were extracted by solid-phase extraction and SFN was extracted by liquid-liquid extraction with ethyl acetate. Chromatographic separation of SFN, SFN-GSH and SFN-NAC was achieved on a C8 reverse phase column with a mobile phase gradient (Mobile Phase A: 10mM ammonium acetate buffer, pH: 4.5 and Mobile Phase B: acetonitrile with 0.1% formic acid) at a flow rate of 0.3 mL/min. The Finnigan LCQ LC-MS/MS was operated under the selective reaction monitoring mode using the electrospray ionization technique in positive mode. The nominal retention times for SFN-GSH, SFN-NAC and SFN were 8.4, 11.0, and 28.2 min,, respectively. The method was linear for SFN and its metabolites with correlation coefficients >0.998 for all analytes. The limit of quantification was 0.01-0.1 microm depending on analyte and matrix, whereas the mean recoveries from spiked plasma and perfusate samples were approximately 90%. The method was further validated according to U.S. Food and Drug Administration guidance in terms of accuracy and precision. Stability of compounds was established in a battery of stability studies, i.e., bench top, auto-sampler and long-term storage stability as well as freeze/thaw cycles. The utility of the assay was confirmed by the analysis of intestinal perfusate and plasma samples from single-pass intestinal perfusion studies with mesenteric vein cannulation in rats.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Mucosa Intestinal/metabolismo , Espectrometria de Massas/métodos , Tiocianatos/metabolismo , Animais , Calibragem , Isotiocianatos , Permeabilidade , Ratos , Ratos Sprague-Dawley , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Sulfóxidos , Tiocianatos/sangue
8.
Methods Mol Med ; 122: 265-84, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16511987

RESUMO

Fatty acids (FAs), especially essential fatty acids (EFAs) and their long chain polyunsaturated fatty acid (LCPUFAs) derivatives, are critical for proper fetal development. The fetus relies on the placental transfer of EFAs from the maternal circulation for development. In fact, fatty acid transfer is highly directional from the mother to the fetus. Significant changes in placental fatty acid transport and metabolism, the two primary processes that govern placental FA supply from mother to fetus, can subsequently result in aberrant fetal fatty acid/lipid homeostasis and dramatically increase the risk of abnormal fetal development. Besides passive diffusion, specific fatty acid transfer conferring proteins can actively mediate directional placental fatty acid uptake and transport. Enzymes for fatty acid beta-oxidation and synthesis and the ones participating PUFA metabolism, including cytochrome P450 (mainly CYP4A), cyclooxygenases (COXs), and lipooxygenases (LOXs), have also been identified in the placenta. Methods for studying functional placental fatty acid uptake/transport/metabolism are discussed, focusing on an in vitro placental trophoblast model and long chain unsaturated fatty acids. The relevant theory of FA transport pathways, kinetic data analysis (uptake rates, permeability, influx/efflux ratio, Km, and so on) and high-performance liquid chromatography identification are also discussed.


Assuntos
Bioensaio/métodos , Técnicas de Cultura de Células/métodos , Ácidos Graxos/metabolismo , Placenta/metabolismo , Animais , Linhagem Celular , Proteínas de Transporte de Ácido Graxo , Feminino , Gravidez , Ratos , Trofoblastos/metabolismo
9.
Cancer Res ; 64(17): 6214-24, 2004 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-15342407

RESUMO

The efficacy of chemotherapy of lung cancer is limited by the development of resistance in cancer cells during treatment. In most lung cancers, this resistance is associated with the overexpression of (a) multidrug resistance-associated protein (MRP) responsible for drug efflux from the cancer cells (pump resistance) and (b) BCL2 protein that activates antiapoptotic cellular defense (nonpump resistance). A novel liposomal proapoptotic anticancer drug delivery system was developed to enhance anticancer efficacy of the well-established drug doxorubicin (DOX). This multicomponent drug delivery system was tested on multidrug-sensitive and -resistant human small-cell lung cancer cells. The drug delivery system includes four components: (a) liposome as a carrier, (b) DOX as an inductor of apoptosis, (c) antisense oligonucleotides (ASOs) targeted to MRP1 mRNA as a suppressor of pump resistance, and (d) ASOs targeted to BCL2 mRNA as a suppressor of nonpump resistance. Intracellular internalization of ASOs and DOX; the influence of the proposed system on the expression of genes and proteins involved in the multidrug resistance, cytotoxicity, and apoptosis induction and antiapoptotic defense; and the activity of caspases were studied. It was found that the proposed liposomal delivery system successfully delivered ASOs and DOX to cell nuclei, inhibited MRP1 and BCL2 protein synthesis, and substantially increased the anticancer action of DOX by stimulating the caspase-dependent pathway of apoptosis in multidrug-resistant human lung cancer cells.


Assuntos
Carcinoma de Células Pequenas/tratamento farmacológico , Neoplasias Pulmonares/tratamento farmacológico , Proteínas Associadas à Resistência a Múltiplos Medicamentos/antagonistas & inibidores , Oligonucleotídeos Antissenso/administração & dosagem , Proteínas Proto-Oncogênicas c-bcl-2/antagonistas & inibidores , Apoptose/efeitos dos fármacos , Carcinoma de Células Pequenas/genética , Carcinoma de Células Pequenas/metabolismo , Caspase 3 , Caspases/metabolismo , Doxorrubicina/administração & dosagem , Doxorrubicina/farmacocinética , Sistemas de Liberação de Medicamentos , Humanos , Lipossomos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Proteínas Associadas à Resistência a Múltiplos Medicamentos/biossíntese , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Oligonucleotídeos Antissenso/genética , Oligonucleotídeos Antissenso/farmacocinética , Proteínas Proto-Oncogênicas c-bcl-2/biossíntese , Proteínas Proto-Oncogênicas c-bcl-2/genética , RNA Mensageiro/genética , Células Tumorais Cultivadas
10.
Circulation ; 105(15): 1776-9, 2002 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-11956118

RESUMO

BACKGROUND: Elevated homocysteine levels are associated with increased coronary risk, and it has been suggested that homocysteine screening may provide a method to identify high-risk patients for aggressive primary prevention. METHODS AND RESULTS: Homocysteine was measured at baseline and after 1 year among 5569 participants in the Air Force/Texas Coronary Atherosclerosis Prevention Study (AFCAPS/TexCAPS), a randomized trial of lovastatin in the primary prevention of acute coronary events. The effects of homocysteine, LDL cholesterol, and lovastatin on risk were assessed over 5.2 years of trial follow-up. Median baseline homocysteine levels were significantly higher among study participants who subsequently had acute coronary events compared with those who did not (12.1 versus 10.9 micro;mol/L, P<0.001). The relative risks of future events from lowest (referent) to highest quartile of homocysteine were 1.0, 1.6, 1.6, and 2.2 (P<0.001). These effects were similar among those allocated to lovastatin and those allocated to placebo and were modestly attenuated after adjustment for other traditional risk factors. As predicted, the subgroup of participants with elevated LDL cholesterol and elevated homocysteine levels were at high risk and benefited greatly from statin therapy (relative risk, 0.46; 95% CI, 0.29 to 0.75; number needed to treat=26). However, in contrast to findings in this trial for C-reactive protein, homocysteine evaluation did not help to define low LDL subgroups with different responses to lovastatin therapy. CONCLUSIONS: Although homocysteine predicted future coronary events in AFCAPS/TexCAPS, we found little evidence that homocysteine evaluation provided an improved method to target statin therapy among those with low-to-normal LDL cholesterol levels.


Assuntos
Anticolesterolemiantes/uso terapêutico , Doença das Coronárias/diagnóstico , Doença das Coronárias/prevenção & controle , Homocisteína/sangue , Lovastatina/uso terapêutico , Doença Aguda , Idoso , Proteína C-Reativa/análise , LDL-Colesterol/sangue , Doença da Artéria Coronariana/prevenção & controle , Método Duplo-Cego , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/diagnóstico , Fatores de Risco
11.
Lancet ; 364(9436): 771-7, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15337403

RESUMO

BACKGROUND: The effects of cholesterol-lowering treatment with statins on mortality and risk of cancer beyond the usual 5-6-year trial periods are unknown. We extended post-trial follow-up of participants in the Scandinavian Simvastatin Survival Study (4S) to investigate cause-specific mortality and incidence of cancer 5 years after closure of the trial. METHODS: 4S was a randomised double-blind trial of simvastatin or placebo in patients with coronary heart disease, serum total cholesterol 5.5-8.0 mmol/L, and serum triglycerides 2.5 mmol/L or lower. The double-blind period lasted for a median of 5.4 years (range for survivors 4.9-6.3) and ended in 1994. After the trial, most patients in both groups received open-label lipid-lowering treatment. National registers were used to assess mortality and causes of death and cancer incidence in the original treatment groups for a median total follow-up time of 10.4 years (range for survivors 9.9-11.3). Analysis was by intention to treat. FINDINGS: 414 patients originally allocated simvastatin and 468 assigned placebo died during the 10.4-year follow-up (relative risk 0.85 [95% CI 0.74-0.97], p=0.02), a difference largely attributable to lower coronary mortality in the simvastatin group (238 vs 300 deaths; 0.76 [0.64-0.90], p=0.0018). 85 cancer deaths arose in the simvastatin group versus 100 in the placebo group (0.81 [0.60-1.08], p=0.14), and 227 incident cancers were reported in the simvastin group versus 248 in the placebo group (0.88 [0.73-1.05], p=0.15). Incidence of any specific type of cancer did not rise in the simvastatin group. INTERPRETATION: Simvastatin treatment for 5 years in a placebo-controlled trial, followed by open-label statin therapy, was associated with survival benefit over 10 years of follow-up compared with open-label statin therapy for the past 5 years only. No difference was noted in mortality from and incidence of cancer between the original simvastatin group and placebo group.


Assuntos
Anticolesterolemiantes/uso terapêutico , Doença das Coronárias/prevenção & controle , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Neoplasias/epidemiologia , Sinvastatina/uso terapêutico , Adulto , Idoso , Doença das Coronárias/sangue , Doença das Coronárias/mortalidade , Seguimentos , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/efeitos adversos , Incidência , Masculino , Pessoa de Meia-Idade , Neoplasias/mortalidade , Países Escandinavos e Nórdicos/epidemiologia , Sinvastatina/efeitos adversos , Taxa de Sobrevida
12.
Toxicol Sci ; 84(2): 287-300, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15647598

RESUMO

Di-(2-ethylhexyl)-phthalate (DEHP) is a widely used plasticizer and ubiquitous environmental contaminant. The potential health hazards, including teratogenicity, from exposure to DEHP may be related to the role of DEHP or its metabolites in the trans-activation of peroxisome proliferator-activated receptors (PPARs). Fetal essential fatty acid (EFA) homeostasis is controlled by directional transfer across the placenta through a highly regulated process, including PPAR activation. Using HRP-1 rat trophoblastic cells, the effects of DEHP and two of its metabolites, mono-(2-ethylhexyl)-phthalate (MEHP) and 2-ethylhexanoic acid (EHA), on the mRNA and protein expression of the three known PPAR isoforms (alpha, beta, and gamma), fatty acid transport protein 1 (FATP1), plasma membrane fatty acid binding protein (FABPpm), and the heart cytoplasmic fatty acid binding protein (HFABP) were investigated. This study also investigated the functional effects of exposure on the uptake and transport of six long chain fatty acids (LCFAs): arachidonic acid (AA), docosahexaenoic acid (DHA), linoleic acid (LA), alpha-linolenic acid (ALA), oleic acid (OA), and stearic acid (SA). In the presence of DEHP, MEHP, and EHA, the expression of PPARalpha, PPARgamma, FATP1, and HFABP were up-regulated in a dose- and time- dependent manner, while PPARbeta and FABPpm demonstrated variable expression. The uptake rates of EFAs (AA, DHA, LA, ALA) increased significantly upon exposure, and the transport of AA (omega-6) and DHA (omega-3) were directionally induced. These results suggest that DEHP, MEHP, and EHA can influence EFA transfer across HRP-1 cells, implying that these compounds may alter placental EFA homeostasis and potentially result in abnormal fetal development.


Assuntos
Dietilexilftalato/análogos & derivados , Dietilexilftalato/toxicidade , Ácidos Graxos Insaturados/metabolismo , Receptores Ativados por Proliferador de Peroxissomo/metabolismo , Teratogênicos/toxicidade , Trofoblastos/efeitos dos fármacos , Regulação para Cima/efeitos dos fármacos , Animais , Transporte Biológico/efeitos dos fármacos , Caproatos/toxicidade , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Linhagem Celular , Proteínas de Transporte de Ácido Graxo , Proteínas de Ligação a Ácido Graxo , Homeostase , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Isoformas de Proteínas , RNA Mensageiro/metabolismo , Ratos , Trofoblastos/metabolismo
13.
Toxicology ; 184(2-3): 125-33, 2003 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-12499115

RESUMO

The intestinal transport of chlorpyrifos (CPF), an organothiophosphate pesticide, was investigated using the single-pass intestinal perfusion (SPIP) technique in male, Sprague-Dawley rats. SPIP was performed in each isolated region of the small intestine (i.e. duodenum, jejunum and ileum) with three concentrations of CPF (0.1, 2.0 and 10 microM) at a flow rate of 0.25 ml/min. Preliminary binding and stability studies were conducted to ensure that the loss of CPF in the SPIP study can be attributed to intestinal absorption. The effective permeability (P(eff)) of CPF was determined for each segment and concentration. CPF exhibits a high intestinal permeability over the length of the small intestine indicative of compounds that are well absorbed. Decreases in permeability values at the highest CPF concentration studied in the duodenum and ileum suggest a saturable transport process. Based on these results, passive, transcellular diffusion dominates the intestinal transport mechanism of CPF, with a saturable transport process evident in the duodenum and ileum. The P(eff) of CPF is in the range of drugs with high intestinal permeability and high fraction of dose absorbed indicating that CPF readily crosses the intestine. The dependence of CPF's P(eff) on concentration in the duodenum and ileum suggests that CPF is transported by a combination of mechanisms across the intestine. Using established relationships, the human fraction dose absorbed for CPF was estimated to be >99%. The permeability values obtained from this study may be useful in models of exposure assessment.


Assuntos
Clorpirifos/farmacocinética , Inseticidas/farmacocinética , Absorção Intestinal/fisiologia , Algoritmos , Animais , Clorpirifos/administração & dosagem , Cromatografia Líquida de Alta Pressão , Técnicas In Vitro , Inseticidas/administração & dosagem , Masculino , Perfusão , Ligação Proteica , Ratos , Ratos Sprague-Dawley , Espectrofotometria Ultravioleta
14.
Am J Health Syst Pharm ; 59(8): 713-5, 2002 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-11977855

RESUMO

The stability of calcitonin salmon in calcitonin salmon nasal spray at elevated temperatures was studied. Vials of calcitonin salmon nasal spray (2200 IU/mL) were stored for three days at 25, 40, or 60 degrees C or for three days at the same temperatures followed by two weeks at 5 degrees C and two additional weeks at 25 degrees C. Concentrations of calcitonin salmon and calcitonin C (a degradation product) were determined relative to a calcitonin salmon reference standard by high-performance liquid chromatography. Calcitonin salmon was stable under all study conditions except initial storage at 60 degrees C followed by two weeks at 5 degrees C and two weeks at 25 degrees C. The stability results were the same when determinations were made in terms of calcitonin C, which exceeded a 5% concentration only for samples stored for the extended period after initial storage at 60 degrees C. Calcitonin salmon remained stable in nasal spray after being stored for three days at 25 or 40 degrees C followed by two weeks at 5 degrees C and two weeks at 25 degrees C. Stability was lost during extended storage after initial storage at 60 degrees C.


Assuntos
Calcitonina/química , Administração Intranasal , Estabilidade de Medicamentos , Armazenamento de Medicamentos , Temperatura
16.
Arch Toxicol ; 81(1): 57-62, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16951938

RESUMO

Lipids, especially essential fatty acids (EFAs), play critical roles in guiding proper fetal development. Exposure to xenobiotics that may alter the fetal supply of EFAs/lipids could potentially lead to fetotoxicity. In this study, we investigated the effects of the peroxisome proliferator chemical, di-(2-ethylhexyl)-phthalate (DEHP), on the lipid metabolomic profile of the rat fetal brain upon maternal exposure during gestation. Female Sprague-Dawley rats were orally gavaged with a control vehicle or DEHP (1,500 mg/kg) from gestational day (GD) 0 to GD 19 and fetal brain tissue was isolated at GD 20. The concentrations of 11 lipid classes [free fatty acid, free cholesterol (FC), cholesterol ester (CE), diacylglycerol (DAG), triacylglyceride, phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine (PS), lysophosphatidylcholine (LYPC), cardiolipin, and sphingomyelin (SM)] were determined, as well as the differences in the composition of individual fatty acids. The total lipid concentration decreased with DEHP exposure, particularly for FC and SM, by 33 and 54%, respectively. The same trend was observed in the fatty acid compositions, particularly the unsaturated fatty acids, where a greater decrease was observed with longer fatty acid chain length. The compositions of docosahexaenoic acid decreased significantly in five lipid classes (P < 0.05), including CE (43%), DAG (60%), PS (33%), LYPC (35%), and SM (40%). In contrast, the most remarkable reduction of arachidonic acid presented in two lipid classes, CE and LYPC, with a decrease of up to 33%. These results suggest that in utero exposure to DEHP alters the lipid metabolome in the fetal brain, which may lead to aberrant neurodevelopment.


Assuntos
Encéfalo/efeitos dos fármacos , Dietilexilftalato/toxicidade , Lipídeos/análise , Análise de Variância , Animais , Ácido Araquidônico/análise , Encéfalo/embriologia , Encéfalo/metabolismo , Química Encefálica/efeitos dos fármacos , Ésteres do Colesterol/análise , Ácidos Docosa-Hexaenoicos/análise , Poluentes Ambientais/química , Poluentes Ambientais/toxicidade , Ácidos Graxos Monoinsaturados/análise , Ácidos Graxos Ômega-3/análise , Ácidos Graxos Insaturados/análise , Feminino , Cromatografia Gasosa-Espectrometria de Massas/métodos , Metabolismo dos Lipídeos/efeitos dos fármacos , Lipídeos/química , Lisofosfatidilcolinas/análise , Masculino , Exposição Materna , Ratos , Ratos Sprague-Dawley , Triglicerídeos/análise
17.
Arch Toxicol ; 80(5): 293-8, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16328440

RESUMO

The highly directional maternal-to-fetal transfer of essential fatty acids (EFAs) across the placenta plays a critical role in guiding proper fetal development. Exposure to xenobiotics that may alter the fetal supply of EFAs/lipids could lead to fetal toxicity. Since the placenta is the first fetal arising organ that regulates fetal fatty acid homeostasis, the fatty acid/lipid composition in the placenta may serve as an indicator of fetal composition. In this study, we investigated the effects of the peroxisome proliferator chemical di-(2-ethylhexyl)-phthalate (DEHP), a widely used plasticizer and ubiquitous environmental contaminant, and its selective metabolites, mono-(2-ethylhexyl)-phthalate (MEHP) and 2-ethylhexanoic acid (EHA) on the lipid metabolome in a rat HRP-1 trophoblast model. The concentrations of ten lipid classes (cholesterol esters, diacylglycerol, triacylglycerides, phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, lysophosphatidylcholine, cardiolipin, and sphingomyelin) were determined, as well as the individual fatty acid compositions, especially the omega-3 and omega-6 family of EFAs. The level of each lipid class was significantly increased upon exposure to the agents, with MEHP and EHA generally showing higher increases than DEHP. The same trends were observed in comparing the fatty acid compositions. For example, the omega-3/omega-6 fatty acids ratio did not change, although the levels of omega-3 and omega-6 fatty acids were significantly elevated upon exposure. These results suggest that DEHP and its metabolites can alter lipid metabolome in a rat placental cell line, implying that these compounds may contribute to aberrant placental EFA/lipid homeostasis caused by peroxisome proliferation, and potentially result in abnormal fetal development.


Assuntos
Dietilexilftalato/toxicidade , Poluentes Ambientais/toxicidade , Metabolismo dos Lipídeos , Proliferadores de Peroxissomos/toxicidade , Plastificantes/toxicidade , Trofoblastos/efeitos dos fármacos , Animais , Caproatos/toxicidade , Linhagem Celular , Dietilexilftalato/análogos & derivados , Dietilexilftalato/metabolismo , Ácidos Graxos/metabolismo , Feminino , Plastificantes/metabolismo , Ratos , Trofoblastos/metabolismo
18.
J Microencapsul ; 23(6): 643-53, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-17118880

RESUMO

The aim of this study was to investigate how glass transition temperature (Tg) influenced polymer microsphere formation and degradation of three chemically, similar novel salicylatebased poly(anhydride-esters): poly[1,6-bis(o-carboxyphenoxy)hexanoate] (CPH), Tg = 59 degrees C; poly[1,8-bis(o-carboxyphenoxy)octanoate] (CPO), Tg = 30 degrees C; and poly[1,10-bis(ocarboxyphenoxy) decanoate] (CPD), Tg = 27 degrees C. Microspheres of these polymers were prepared using a modified oil-in-water solvent evaporation method and processed by either resuspension or washed by centrifugation. The morphology of the microspheres determined by scanning electron microscopy (SEM) revealed that an extra washing step appears to increase aggregation as the Tg decreases; whereas only limited aggregation occurred in the polymer with the lowest Tg, CPD, in those not washed by centrifugation. Residual polyvinyl alcohol apparently affected the drug release rates from the microspheres by a stabilization process that produced an 8 h lag time and a 5% decrease in the amount of drug released over a 7 day period compared to microspheres washed free of PVA. These results demonstrate that salicylate-based poly(anhydride-esters) with sufficiently high Tgs, can be processed into microspheres that release salicylate over a time period amenable for drug delivery applications.


Assuntos
Anidridos/química , Materiais Biocompatíveis/química , Polímeros/química , Ácido Salicílico/química , Biodegradação Ambiental , Preparações de Ação Retardada/química , Preparações de Ação Retardada/farmacocinética , Ésteres/química , Vidro/química , Técnicas In Vitro , Microscopia Eletrônica de Varredura , Microesferas , Estrutura Molecular , Peso Molecular , Tamanho da Partícula , Transição de Fase , Álcool de Polivinil/química , Fatores de Tempo , Temperatura de Transição , Água/química
19.
Eur Heart J ; 27(23): 2755-62, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16891382

RESUMO

AIMS: To examine the prognostic importance of weight-change in patients with coronary artery disease (CAD), especially following acute myocardial infarction (AMI). METHODS AND RESULTS: In 4360 AMI patients (OPTIMAAL trial) without baseline oedema, we assessed 3-month weight-change, baseline body mass index (BMI), demographics, patient history, medication, physical examination, and biochemical analyses. Weight-change was defined as change >+/-0.1 kg/baseline BMI-unit. Patients were accordingly categorized into three groups; weight-loss, weight-stability, and weight-gain. Our findings were validated in 4012 AMI patients (CONSENSUS II trial) and 4178 stable CAD patients (79% with prior AMI, 4S trial). Median follow-up was 2.7 years, 3 months, and 4.4 years, respectively. In OPTIMAAL, 3-month weight-loss (vs. weight-stability) independently predicted increased all-cause death [n=471; hazard ratio (HR) 1.26; 95% CI 1.01-1.56; P=0.039] and cardiac death (n=299, HR 1.33, 95% CI 1.02-1.73, P=0.034). Weight-gain yielded risk similar to weight-stability (HR 1.07, P=0.592 and 0.97, P=0.866, respectively). In CONSENSUS II, 3-month weight-loss independently predicted increased mortality (HR 3.87, P=0.008). Weight-gain yielded risk similar to weight-stability (HR 1.11, P=0.860). In 4S, 1-year weight-loss independently predicted increased mortality (HR 1.44, P=0.004). Weight-gain conferred risk similar to weight-stability (HR 1.05, P=0.735). CONCLUSION: In patients following AMI or with stable CAD, weight-loss but not weight-gain was independently associated with increased mortality risk.


Assuntos
Peso Corporal/fisiologia , Doença da Artéria Coronariana/mortalidade , Infarto do Miocárdio/mortalidade , Idoso , Índice de Massa Corporal , Causas de Morte , Consenso , Doença da Artéria Coronariana/fisiopatologia , Feminino , Humanos , Masculino , Infarto do Miocárdio/fisiopatologia , Prognóstico , Ensaios Clínicos Controlados Aleatórios como Assunto , Fatores de Risco
20.
Mol Pharm ; 2(6): 481-90, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16323955

RESUMO

Cyclooxygenase (COX) catalyzes the rate-limiting step in the conversion of essential fatty acids (EFAs) to bioactive molecules such as prostaglandins (PGs), which play critical roles in many aspects of female reproduction and in fetal development. There are two primary related COX isoforms, the constitutively expressed COX-1 and the inducible COX-2. Although the expression of COX-1 and COX-2 has been demonstrated in the amnion, chorion, and decidua, relatively little information exists with regard to their expression and physiological function in the placenta during gestation. In this study, we have elucidated the spatial and temporal patterns of COX-1 and COX-2 expression in the labyrinthine and junctional zones of the developing rat placenta, in the human term placenta, and in the BeWo human trophoblast model using semiquantitative RT-PCR, Western blot, and immunohistochemical analyses. The mRNA and protein expression of COX-1 and COX-2 were demonstrated in the developing rat placenta with increasing expression observed toward parturition. COX-2 exhibited greater expression than COX-1 after mid-gestation and had a corresponding shift in spatial expression from the labyrinthine to the junctional zone at term. COX-1 and -2 were also expressed in human term placenta, while BeWo cells exhibited moderate expression of COX-1 and weak expression of COX-2. The results demonstrate that COX-1 and COX-2 are expressed in the rat and human placentas. The differential expression patterns in the rat placenta, especially of COX-2, imply that there may be gestational changes in the biosynthesis of PGs and other potential bioactive EFA metabolites. Establishing the expression of the COX isoforms provides a framework for future investigations into the functional and physiological significance of COX-1 and COX-2 in the placenta, particularly with respect to influencing normal pregnancy and fetal development, and to provide insights into therapeutic utilization of COX inhibitors in pregnancy.


Assuntos
Ciclo-Oxigenase 1/metabolismo , Ciclo-Oxigenase 2/metabolismo , Placenta/enzimologia , Trofoblastos/enzimologia , Animais , Sequência de Bases , Linhagem Celular , Ciclo-Oxigenase 1/genética , Ciclo-Oxigenase 2/genética , Primers do DNA , Feminino , Desenvolvimento Fetal , Regulação da Expressão Gênica no Desenvolvimento , Regulação Enzimológica da Expressão Gênica , Humanos , Modelos Biológicos , Gravidez , Terceiro Trimestre da Gravidez , RNA Mensageiro/genética , Ratos , Ratos Sprague-Dawley , Reação em Cadeia da Polimerase Via Transcriptase Reversa
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